Higher resolution will be sharper.
Unfortunately AMOLED historically has issues with white often looking blue/green, this has gotten a lot better in the past couple years.
Colors on AMOLED are by default way blown out like a TV in store display mode. Most phones have a way to correct that and give somewhat accurate colors, nexus buries sRGB in developer settings for this, because if you are building an app that's the only time you need accurate colors apparently? Stupid.
Many AMOLED screens have discolorations like yellowing in certain areas or whole screen. Sometimes you have to exchange to get a good one.
I've never had to adjust or exchange a recent iPhone, their displays always look great.